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Wednesday, January 30, 2013

My friend Mike, over at his Louisville Fossils blog, sent me a couple of brachiopods from Kentucky that I didn't have in my collection.

The first one is a huge Syringothyris Pedicle valve from the Mississippian aged Muldraugh formation. It's just the single valve and he had to cut it out of the hard limestone, but it's pretty cool! Mike has a more complete one on his blog here.

Anterior

Posterior

The other brachiopod is Pentamerus nysius from the Louisville Limestone of Kentucky which is Silurian in age (Homerian to Gorstian stage). Again it's just a single valve (in this case the Brachial) but you can see the outline of the Pedicle valve just above the tip. Mike has one posted on his blog here.

Monday, January 28, 2013

Goniatites were common thoughout the Paleozoic until going extinct during the Permian. they were related to true Ammonites but often were considered Ammonoids. The specimen below comes from the Caney Shale (Mississippian epoch, Serpukhovian stage) near Fittstown, Oklahoma.

Saturday, January 26, 2013

Below are some strange floating crinoid fossils that were given to me by my friend Herb. I believe they are dorsal cups from a Agassizocrinus laevis as they seem to match the picture and description given in "Index Fossils of N. America", Shimer and
Shrock, M.I.T. press, 1944 (pg 175-176, pl.61). The description of these crinoids indicates that the plates of the dorsal cup were fused in adult specimens but juvenile specimens might still show some detail as well as a stem attachment point.

Specimen 1

Top surface where the arms would have attached

Profile 1

Profile 2

Base of the dorsal cup

Specimen 2. Top surface where the arms would have attached

Profile1

Profile 2

Base of the dorsal cup

These fossils came from Chesterian aged rocks near Leitchfield, Kentucky. Chesterian is an old North American stage name for rocks that are classified by the ICS as being in the late middle to upper Mississippian Epoch (upper Visean to Serpukhovian stage).
After talking with Herb he confirmed that they came from the Ste. Genevieve formation. Thank you Herb for giving me these fossils!

Thursday, January 24, 2013

Here is an oddball brachiopod I've had in my collection for a while but didn't really know much about. The label that came with it listed Unispirifer from the Banff Formation in Western Alberta. A quick search on Paleodb.org found it hailed from the lower Carboniferous (Mississippian, Tournasian stage). It's a bit rough but the pedicle valve shows a little detail still. Update 01/27/13: Sharp eyed reader Howard pointed out that this is more likely Cleiothyridina lata, not an Unisprifer.

Sunday, January 20, 2013

More than any other species of trilobite, Dalmanites is the one most often see for sale from the Rochester Shale. I purchased this nice little pyritized specimen of Dalamnites limulurus from a rock shop in Basdell, NY (Past and Present). It's smaller than most that I see offered but I like the golden pyrite look and the slight twisting of the fossil.

This is most likely a molt but the way that the body is slightly twisted and bent makes it look like it died in place. Maybe smothered by anoxic conditions (which would explain the pyrite preservation)?

The specimen came from the Rochester Shale which is dated to the
Sheinwoodian/Homerian stage of the Wenlock epoch of the Silurian.

Friday, January 18, 2013

Arctinurus boltoni is one of the largest trilobites that can be found in the Rochester Shale of New York. It's parts are easily identified by their pustulose (small bumps on the surface of the carapace) nature.

I purchased this specimen of a pygidium from a rock shop in Basdell, NY (Past and Present). It is partially an impression with a little of the recrystallized carapace intact. The fossil has been painted with a preservative coating to prevent the fossil from falling apart.

The specimen came from the Rochester Shale which is dated to the Sheinwoodian/Homerian stage of the Wenlock epoch of the Silurian.

Here is a whole specimen on my friend Joe's website.
Mike at Lousiville Fossils has some pieces pictured on his blog from the Waldron Shale which is roughly equivalent to the Rochester Shale.

Monday, January 14, 2013

Specimens of Dictyonella reticulata are easy to pick out of a lineup. They have a very distinctive exterior that looks like hatch marks or it is covered with a bryozoan. In actuality the pattern is related to a defensive mechanism whereby the each diamond shaped pit had a small tube extending into the shell. Through that tube the brachiopod could ooze a noxious chemical to keep predators from eating it and opportunistic larvae from settling on it. Think of them as the prototype to having actual spines.

Pedicle valve

Anterior

Brachial valve

Posterior

Profile

The above specimen came from the Waldron shale in Indiana which is Silurian (Sheinwoodian to Homerian stage) in age.

There are some who would ID this fossil as an Eichwaldia reticulata which is an older name.
A review of the "Treatise on Invertebrate Paleontology - Part H - Brachiopoda V1" edited by Moore (1965) has the following description of the two genera (which are in the same family) on page 360:

Volume 8, part 2
of "the Paleontology of New York" by James Hall describes Eichwaldia
on page 307 and illustrates it on plate LXXXIII (88 for those unfamiliar
with roman numerals).

Also, Mike over at Louisville Fossils points out that the genera Dictyonella was renamed Eodictyonella in 1994 by Anthony D. Wright in his paper titled "Eodictyonella, a new name for Dictyonella Hall, 1868, not Dictyonella Schmidt, 1868" in the Journal of Paleontology, July 1994, v. 68, p. 908-909

Here is a Dictyonella corallifera from the Irondequoit limestone of New York which is roughly the same age as the Waldron shale.

Saturday, January 12, 2013

The small brachiopod below was purchased labelled as a Nucelospria pisiformis from the Waldron shale. I am not entirely familiar with the fauna of the Waldron shale, but this looks very similar to shells I see identified as Whitfieldella nitida. A quick review of the "Index Fossils of North America" by Shimer and Shrock (pg 331, pl. 126, 127) does indeed lend creedence to my suspicions.

Pedicle valve

Anterior

Brachial valve

Posterior

Profile

The specimen above came from the Waldron shale in Indiana which is Silurian (Sheinwoodian to Homerian stage) in age.

About Me

I'm a 40-something, life long student of Geology living in Philadelphia. My interests include Photography, Architecture and History among other things. When not cleaning my recent finds you'll find me in my backyard Hybridizing Daylilies or working in my garden. This Blog is an outlet for me to express my interest in fossils, catalog my collection and coalesce my thoughts and research into a useful medium.